Abstract: Ultra-high performance concrete, characterized by its exceptional mechanical properties and durability, has been extensively employed in large-scale public buildings and military protective structures. Investigating the mechanical behavior of ultra-high performance concrete under dynamic loading and establishing its viscoplastic damage constitutive model are of critical importance for engineering applications. This study systematically investigates the uniaxial compressive viscoplastic damage constitutive model of ultra-high performance concrete. By developing a viscoplastic theoretical framework within effective stress space, the theoretical correlation between the uniaxial dynamic compression model and the uniaxial static compression model is revealed, and the dynamic evolution law of the internal variable considering the rate sensitive effect is clarified. On this basis, the uniaxial compression viscoplastic damage constitutive model of ultra-high performance concrete is established, and the expression for the dynamic increase factor of compressive strength considering the effect of fiber content is proposed. The proposed expression for the dynamic increase factor of compressive strength and the viscoplastic damage constitutive model are verified through a comparison with the experimental data in literature. The results show that the proposed model can accurately reproduce the plastic evolution law, damage evolution law and stress-strain relationship of ultra-high performance concrete under uniaxial compression, which can provide a reference for the nonlinear analysis of ultra-high performance concrete.